The prior art capping machines which are commercially available, utilize for the most part a lever arm which pulls the cap from the chute end into the area between the chuck and the top of the container which is being capped. This, in turn, requires a clearance between the container tops and the chuck to allow for the thickness of the lever arm plus the height of the cap that the lever arm has picked out of the chute. This clearance distance is normally fixed on the prior art machines and is selected such as to allow room for the maximum cap height that the machine is designed to handle. Additionally, the chuck in the prior art devices is required to make two downward and upward strokes during each capping cycle because the chuck must come down once over the lever arm to pick up the cap, then retract to allow the lever arm to move back to its position behind the cap chute and thereafter must make another downward and upward movement as the cap is actually being applied onto the container. This means that at a capping rate of, for example, fifty caps per minute, the prior art capping machines must perform one hundred reciprocating strokes per minute which thus limits the capping rate. Though the clearance between the chuck and the top of the containers varies from machine to machine, it is generally of the order of two inches or more. However, the length of the stroke of the chuck determines the length of time required to complete the stroke and therewith the cycle rate. Additionally, the prior art capping machines also utilize frequently a pivot chute which is raised to allow the cap pick-up lever arm to pass underneath the chute end after the cap has been placed into the chuck.
A different approach has been suggested in the U.S. Pat. No. 3,212,231 in which the spindle carrying the capping head is adapted to be pivoted from a position over the bottle necks into an inclined position in which a plunger or ram transfers the cap in the chute end onto the chuck. In addition to the pivotal motion of the spindle together with the chuck, the chuck also undergo vertical movement together with the spindle to bring a respective cap into engagement with the bottle neck. These pivot and vertical movements are accomplished in this patent by two separate mechanical systems, which are cam-operated through a number of levers and linkages. The large number of the mechanical components involved results in relatively large moving masses which is not only relatively expensive to manufacture but also imposes physical limitations on the cycle rate at which the machine can operate. Furthermore, the spindle drive in this patent is essentially a friction drive utilizing friction wheels frictionally driving the spindle when the latter are in the vertical position. Such friction drive is subject to wear, a factor further enhanced by the continuous engagement and disengagement, and additionally requires a delicate adjustment and alignment of the parts to maintain a balanced, uniform driving action to the spindles. As there is slippage in any friction drive, the actual application of torque of the cap is, in all likelihood, a combination of the torque supplied to the spindle by way of the friction drive and the ball detent clutch as disclosed in the patent.